File Name: advantages and disadvantages of extrusion process .zip
- Extrusion Process:
- What is Extrusion Process: Working, Types, Applications, Advantages
- Extrusion Process | Types, Advantages, Disadvantages, Applications
The extrusion is a method in which the metal is subjected to plastic flow by enclosing the metal in a closed chamber in which the one hole is provided through a die. The material is commonly treated so that it can sustain plastic deformation at an adequately rapid rate and may be removed out of the hole in the die.
In the process, the metal allows the opening provided in the die and comes out as a long piece with the same cross-section as the die-opening. The metal piece provided will have a longitudinal grain flow. The method of extrusion is most generally used for the production of solid and hollow sections of nonferrous metals and alloys e. And some steel products are also made by extrusion. The stock or the material to be extruded is in the shape of cast iron ingots or bullets.
Extrusion may be done hot or cold. Extrusion is a compressed metal forming process. In this process, a piston or plunger is applied to apply a compressive force to the workpiece. Initially, billet or ingot standard size metal workpiece is provided.
This billet is heated in hot extrusion or remains at room temperature and located in an extrusion press The extrusion press is like a piston-cylinder device in which the metal is placed in a cylinder and pushed by the piston. The upper part of the cylinder is fitted with a die. Immediately, a compressive force is applied to this part by a plunger fitted in the press which forces the billet to die.
The die is the small opening of the needed cross-section. This high compressive force allows the work metal to flow through the die and change into the desired shape. Finally, the extruded part is removed from the press and heat-treated for better mechanical properties.
The hot extrusion is the most popular method for developing objects with a fixed cross-sectional profile. The extrusion process is performed at an increased temperature, which maintains the materials from process hardening along with making the procedure of pushing the material through the die simpler. In general, large quantities of hot extrusion are performed using horizontal hydraulic presses that belong to a range of — 12, tons. Here, the pressure range is 30 to MPa 4, to , psi , so lubrication is required.
That lubrication can be obtained by glass powder in case of greater temperature extrusions and oil or graphite for all the lower temperature extrusions. Although hot extruded material is greatly preferred, hot extrusion has a couple of limitations associated with it that are the cost of extrusion machines and their maintenance.
There are two different two types of hot extrusion are as follows. In this process, the material to be extruded is in the form of a block. It is heated to a required temperature and then it is transferred inside a chamber as shown in fig. In the front portion of the chamber, a die with an opening in the shape of the cross-section of the extruded products is fitted. The block of material is pressed from behind by means of ram and a follower pad. Since the chamber is closed on all sides, the heated material is forced to squeeze through the die-opening in the forms of a long strip of the required cross-section.
The process seems simple but the friction between the material and the chamber walls should be overcome by suitable lubrication. When extruding steel products, the high temperature to which the steel has to be heated makes it difficult to find a suitable lubricant.
The problem is determined by applying molten glass as a lubricant. When the lower temperature is used, a mixture of oil and graphite is used as a lubricant.
The arrangement is done as given in the fig. The block of heated metal is inserted into the chamber. It is enclosed on all sides by the container walls except in front Where a ram with the die presses upon the material. When the ram presses backwards, the material has to flow forwards through the opening in the die. The ram is formed hollow so that the bar of extruded metal may pass over it unhindered.
This process is called a backward extrusion process as the flow of material is in a direction opposite to the movement of the ram. In the forward extrusion process the flow of material and ram movement where both in the same direction.
With the help of extruders and extrusion machines, the process of cold extrusion is carried out at room temperature or at moderately high temperatures. The cold extrusion can also be described as the method of shaping a cold metal by striking a slug. This strike is performed with a punch in a closed cavity , which pushes the metal in an upward direction around the punch. This process is also called cold pressing, cold forging, extrusion pressing, and impact extrusion.
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Types of Cold Extrusion. Advantages of Extrusion. Disadvantages of Extrusion. Application of Extrusion. Download PDF. Tags Mechanical engg. Saif M Saif M.
He completed his engineering studies in and is currently working in a large firm as Mechanical Engineer. He is also an author and editor at theengineerspost. Mechanical Engineering. In this article, you'll learn what is a solar panel, how it works? Read more. In this article, you'll learn what is shaft coupling?
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What is Extrusion Process: Working, Types, Applications, Advantages
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Extrusion Process | Types, Advantages, Disadvantages, Applications
Manufacturing companies employ extrusion molding to make products with a consistent cross-section. Common items found in a home made by this process include PVC pipe, rain gutters and even straws. The process works by pressing melted plastic through a die — a tool that provides the correct shape.
Extrusion moulding is a common manufacturing process that shapes materials with the help of a rigid frame called a pattern. The process involves the forcing out, or extruding, of materials through a die in order to create tube-shaped objects. The process starts off with raw plastic materials which are formed at high volumes and using heat.
In the field of mechanical engineering, the Extrusion Process is widely used by the engineers to form an object which has a fixed cross-sectional area. For making the object, the raw material is pushed into a die to provide it with the desired shape. The major function of this process is that the brittle materials can easily be turned into the desired product as in the case of extrusion only the shear stress and compressive stress are encountered in the process.
The extrusion is a method in which the metal is subjected to plastic flow by enclosing the metal in a closed chamber in which the one hole is provided through a die. The material is commonly treated so that it can sustain plastic deformation at an adequately rapid rate and may be removed out of the hole in the die. In the process, the metal allows the opening provided in the die and comes out as a long piece with the same cross-section as the die-opening.
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